Cognitive Radio Transmission under QoS Constraints and Interference Limitations

TL;DR

This paper analyzes the maximum throughput of cognitive radio systems under QoS and interference constraints, proposing optimal power and channel selection strategies considering sensing, fading, and multiple frequency bands.

Contribution

It introduces a state transition model for cognitive radio operation under QoS and interference constraints, deriving optimal power allocation and channel selection methods.

Findings

Effective capacity depends on sensing accuracy and interference limits.

Optimal power and channel strategies improve throughput under constraints.

Numerical results illustrate the impact of system parameters on performance.

Abstract

In this paper, the performance of cognitive transmission under quality of service (QoS)constraints and interference limitations is studied. Cognitive secondary users are assumed to initially perform sensing over multiple frequency bands (or equivalently channels) to detect the activities of primary users. Subsequently, they perform transmission in a single channel at variable power and rates depending on the channel sensing decisions and the fading environment. A state transition model is constructed to model this cognitive operation. Statistical limitations on the buffer lengths are imposed to take into account the QoS constraints of the cognitive secondary users. Under such QoS constraints and limitations on the interference caused to the primary users, the maximum throughput is identified by finding the effective capacity of the cognitive radio channel. Optimal power allocation strategies are obtained and the optimal channel selection criterion is identified. The intricate interplay between effective capacity, interference and QoS constraints, channel sensing parameters and reliability, fading, and the number of available frequency bands is investigated through numerical results.